The AT91 UTMI clock is a PLL generating the 480 MHz USB clock.
Originally, this PLL always had a fixed x40 multiplier, thus requiring
a 12 MHz input clock. Recent SOCs (sama5d2 and sama5d3) have a special
function register for configuring this multiplier, allowing to use
different main clock frequencies.
Signed-off-by: Ingo van Lil <ing...@gmx.de>
---
drivers/clk/at91/clk-utmi.c | 105 +++++++++++++++++++++++++++++++++++++++++--
include/soc/at91/atmel-sfr.h | 2 +
2 files changed, 104 insertions(+), 3 deletions(-)
diff --git a/drivers/clk/at91/clk-utmi.c b/drivers/clk/at91/clk-utmi.c
index aadabd9..d41c38b 100644
--- a/drivers/clk/at91/clk-utmi.c
+++ b/drivers/clk/at91/clk-utmi.c
@@ -14,14 +14,29 @@
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
+#include <soc/at91/atmel-sfr.h>
#include "pmc.h"
+/* default multiplier for SOCs that do not allow configuration via SFR */
#define UTMI_FIXED_MUL 40
+/* supported multiplier settings for SOCs that allow configuration via SFR */
+struct utmi_multipliers {
+ const char *sfr_compatible_name;
+ u8 multipliers[4];
+};
+
+static const struct utmi_multipliers utmi_multipliers[] = {
+ { "atmel,sama5d2-sfr", { 40, 30, 20, 40 } },
+ { "atmel,sama5d3-sfr", { 40, 30, 20, 10 } },
+};
+
struct clk_utmi {
struct clk_hw hw;
struct regmap *regmap;
+ struct regmap *sfr_regmap;
+ const u8 *multipliers;
};
#define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
@@ -66,8 +81,67 @@ static void clk_utmi_unprepare(struct clk_hw *hw)
static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
- /* UTMI clk is a fixed clk multiplier */
- return parent_rate * UTMI_FIXED_MUL;
+ struct clk_utmi *utmi = to_clk_utmi(hw);
+ u8 mul = UTMI_FIXED_MUL;
+
+ if (utmi->sfr_regmap && utmi->multipliers) {
+ u32 regval;
+ regmap_read(utmi->sfr_regmap, AT91_SFR_UTMICKTRIM, ®val);
+ mul = utmi->multipliers[regval & AT91_UTMICKTRIM_FREQ_MASK];
+ }
+
+ return parent_rate * mul;
+}
+
+static long clk_utmi_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct clk_utmi *utmi = to_clk_utmi(hw);
+ unsigned long bestrate = 0;
+ int bestdiff = -1;
+ int i;
+
+ if (!utmi->sfr_regmap || !utmi->multipliers)
+ return *parent_rate * UTMI_FIXED_MUL;
+
+ for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
+ unsigned long tmprate = *parent_rate * utmi->multipliers[i];
+ int tmpdiff;
+
+ if (tmprate < rate)
+ continue;
+
+ tmpdiff = tmprate - rate;
+ if (bestdiff < 0 || bestdiff > tmpdiff) {
+ bestrate = tmprate;
+ bestdiff = tmpdiff;
+ }
+
+ if (!bestdiff)
+ break;
+ }
+
+ return bestrate;
+}
+
+static int clk_utmi_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_utmi *utmi = to_clk_utmi(hw);
+ int i;
+
+ if (!utmi->sfr_regmap || !utmi->multipliers)
+ return rate == parent_rate * UTMI_FIXED_MUL ? 0 : -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
+ if (rate == parent_rate * utmi->multipliers[i]) {
+ regmap_update_bits(utmi->sfr_regmap,
AT91_SFR_UTMICKTRIM,
+ AT91_UTMICKTRIM_FREQ_MASK, i);
+ return 0;
+ }
+ }
+
+ return -EINVAL;
}
static const struct clk_ops utmi_ops = {
@@ -75,10 +149,13 @@ static const struct clk_ops utmi_ops = {
.unprepare = clk_utmi_unprepare,
.is_prepared = clk_utmi_is_prepared,
.recalc_rate = clk_utmi_recalc_rate,
+ .round_rate = clk_utmi_round_rate,
+ .set_rate = clk_utmi_set_rate,
};
static struct clk_hw * __init
at91_clk_register_utmi(struct regmap *regmap,
+ struct regmap *sfr_regmap, const u8 *multipliers,
const char *name, const char *parent_name)
{
struct clk_utmi *utmi;
@@ -98,6 +175,8 @@ at91_clk_register_utmi(struct regmap *regmap,
utmi->hw.init = &init;
utmi->regmap = regmap;
+ utmi->sfr_regmap = sfr_regmap;
+ utmi->multipliers = multipliers;
hw = &utmi->hw;
ret = clk_hw_register(NULL, &utmi->hw);
@@ -115,6 +194,9 @@ static void __init of_at91sam9x5_clk_utmi_setup(struct
device_node *np)
const char *parent_name;
const char *name = np->name;
struct regmap *regmap;
+ struct regmap *sfr_regmap;
+ const u8 *multipliers = NULL;
+ size_t i;
parent_name = of_clk_get_parent_name(np, 0);
@@ -124,7 +206,24 @@ static void __init of_at91sam9x5_clk_utmi_setup(struct
device_node *np)
if (IS_ERR(regmap))
return;
- hw = at91_clk_register_utmi(regmap, name, parent_name);
+ for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
+ sfr_regmap = syscon_regmap_lookup_by_compatible(
+ utmi_multipliers[i].sfr_compatible_name);
+ if (!IS_ERR(sfr_regmap)) {
+ pr_debug("clk-utmi: found sfr node: %s\n",
+ utmi_multipliers[i].sfr_compatible_name);
+ multipliers = utmi_multipliers[i].multipliers;
+ break;
+ }
+ }
+
+ if (IS_ERR(sfr_regmap)) {
+ pr_debug("clk-utmi: failed to find sfr node\n");
+ sfr_regmap = NULL;
+ }
+
+ hw = at91_clk_register_utmi(regmap, sfr_regmap, multipliers,
+ name, parent_name);
if (IS_ERR(hw))
return;
diff --git a/include/soc/at91/atmel-sfr.h b/include/soc/at91/atmel-sfr.h
index 506ea8f..763948e 100644
--- a/include/soc/at91/atmel-sfr.h
+++ b/include/soc/at91/atmel-sfr.h
@@ -17,6 +17,7 @@
/* 0x08 ~ 0x0c: Reserved */
#define AT91_SFR_OHCIICR 0x10 /* OHCI INT Configuration Register */
#define AT91_SFR_OHCIISR 0x14 /* OHCI INT Status Register */
+#define AT91_SFR_UTMICKTRIM 0x30 /* UTMI Clock Trimming Register */
#define AT91_SFR_I2SCLKSEL 0x90 /* I2SC Register */
/* Field definitions */
@@ -28,5 +29,6 @@
AT91_OHCIICR_SUSPEND_B | \
AT91_OHCIICR_SUSPEND_C)
+#define AT91_UTMICKTRIM_FREQ_MASK 0x03
#endif /* _LINUX_MFD_SYSCON_ATMEL_SFR_H */
--
2.9.4
